[Linux-stm32] [PATCH v4 2/3] dt-bindings: arm: stm32: allow TAMP nvram child node for syscon

[Krzysztof Kozlowski]

On Wed, Nov 04, 2026 at 04:20:09PM +0100, Patrice Chotard wrote:
> The STM32 TAMP node (compatible "st,stm32-tamp", "syscon", "simple-mfd")
> exposes its backup registers through an nvram child node described by
> nvmem/st,stm32-tamp-nvram.yaml. That requires the TAMP node to carry
> "#address-cells", "#size-cells", "ranges" and an "nvram at ..." child.
> 
> st,stm32-syscon.yaml uses "additionalProperties: false" and only allowed
> into the DTSI made "make dtbs_check" fail on every STM32MP TAMP node:
> 
>   tamp at 5c00a000 (st,stm32-tamp): 'nvram at 5c00a100', 'ranges' do not match
>   any of the regexes: '^pinctrl-[0-9]+$'
> 
> Allow the addressing properties and the nvram child, gated on the
> st,stm32-tamp compatible so the other syscon variants stay strict.
> "#size-cells" may be 1 or 2: the STM32MP21 soc bus uses two size cells
> (an empty "ranges" requires the node to match its parent) while the
> other STM32MP SoCs use one.
> 
> Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
> ---
>  .../bindings/arm/stm32/st,stm32-syscon.yaml        | 38 ++++++++++++++++++++--
>  1 file changed, 35 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/stm32/st,stm32-syscon.yaml b/Documentation/devicetree/bindings/arm/stm32/st,stm32-syscon.yaml
> index a559f8b03b84..51cb565e05ed 100644
> --- a/Documentation/devicetree/bindings/arm/stm32/st,stm32-syscon.yaml
> +++ b/Documentation/devicetree/bindings/arm/stm32/st,stm32-syscon.yaml
> @@ -43,13 +43,19 @@ properties:
>      const: 1
>  
>    "#size-cells":
> -    const: 1
> +    enum: [1, 2]
> +
> +  ranges: true

Addition of ranges should be separate commit, because you are fixing
existing device which can have phy child.

>  
>  patternProperties:
>    "^phy at 2[48]00$":
>      type: object
>      $ref: /schemas/phy/st,stm32-usb2phy.yaml
>  
> +  "^nvram@[0-9a-f]+$":
> +    type: object
> +    $ref: /schemas/nvmem/st,stm32-tamp-nvram.yaml
> +
>  required:
>    - compatible
>    - reg
> @@ -84,11 +90,37 @@ allOf:
>          - phy at 2800
>      else:
>        properties:
> -        '#address-cells': false
>          '#clock-cells': false
> -        '#size-cells': false
>          phy at 2400: false
>          phy at 2800: false
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: st,stm32-tamp
> +    then:
> +      required:
> +        - "#address-cells"
> +        - "#size-cells"
> +        - ranges

This has ABI impact and is not really necessary, as the child node is
not required either. Drop these three.

> +    else:
> +      properties:
> +        ranges: false
> +      patternProperties:
> +        "^nvram@[0-9a-f]+$": false

Best regards,
Krzysztof